Radiolucencies Part 2

Question 1

Odontogenic tumors are derived from and classified by…

Answer 1

Presence of odontogenic epithelium and/or odontogenic ectomesenchyme

Question 2

List the tumor classifications of odontogenic tumors

Answer 2

1. Odontogenic Epithelium
   -Ameloblastoma
   -Adenomatoid Odontogenic Tumor (AOT)
   -Calcifying Epithelial Odontogeic Tumor
2. Odontogenic Ectomesenchyme
   -Odontogenic Fibroma
   -Odontogenic Myxoma
   -Cementoblastoma
3. Mixed (epithelial and ectomes.)
   -Ameloblastic Fibroma
   -Ameloblastic Fibro-odontoma
   -Compound or Complex Odontoma

Question 3

Ameloblastoma

Answer 3

-Locally invasive benign odontogenic epithelial tumor
-Wide age range
-Mandible (80%), most often posterior
-Slow-growing, painless, unicystic or multicystic/solid (“conventional”) tumor

Question 4

How does an Ameloblastoma look radiographically?

Answer 4

-Unilocular or multilocular radiolucency (does not make enamel)
-Cortical expansion and thinning
-Soap bubble or honeycomb (round loculations) appearanc e
-Can resorb or displace roots
-May be associated with an impacted tooth

Question 5

Ameloblastoma - Histology

Answer 5

-Variety of patterns of enamel organ-like odontogenic epithelium, cystic formation common
-Peripheral cells usually resemble ameloblasts (columnar shape with palisaded nuclei away from basement membrane, “reverse nuclear polarity” or “reverse polarizartion”
-Central cells often more spindled, resemble stellate reticulum

Question 6

Ameloblastoma - smaller vs larger lesions

Answer 6

-Tumor often extends beyond radiographic margin so that recurrence is common when treated with curettage, particularly for larger lesions
-Smaller lesions: aggressive curettage and peripheral ostectomy (bur the bone)
-Larger lesions: marginal or segmental resection (1-2cm beyond radiographic border)
-Follow pt. for recurrence; rare malignant transformation

Question 7

Unicystic Ameloblastoma

Answer 7

-Unilocular lesion that is entirely cystic - no solid component
-Often pericoronal to unerupted 3rd molar
-Tx: “decompression” shrinks the cyst and thickens the epithelial lining allowing easier enucleation
- 10-20% recurrence with enucleation and curettage so less aggressive than conventional ameloblastoma

Question 8

Peripheral Ameloblastoma

Answer 8

-Remember “central” means within the bone vs “peripheral” means in soft tissue outside of bone
-Painless nodule of alveolar or gingival mucosa
-It is rare; any odontogenic cyst or tumor can do this
-Tx: excision with limited recurrence. So tx is similar to POF, PG etc

Question 9

Other benign odontogenic tumors

Answer 9

-Amelobastic Fibroma: posterior jaws, <20yrs, typically unilocular RL associated with impacted tooth
-Odontogenic Fibroma: both jaws, wide age range

Question 10

Note: Odontogenic Malignancy

Answer 10

-There are malignant odontogenic tumors and you can have malignant transformation of an odontogenic cyst
-May have pain, paresthesia, ill-defined border with cortical destruction rather than just expansion/thinning

Question 11

For a unilocular or multilocular radiolucency in the jaw, what should be your diff. dx for a pericoronal odontogenic lesions

Answer 11

-Dentigerous cyst
-Odontogenic keratocyst (OKC)
-Ameloblastoma (unicystic or conventional)
-Other benign odontogenic tumor

Question 12

For a unilocular or multilocular radiolucency in the jaw, what should be your diff. dx for a periapical/periradicular (around the teeth/alveolus) odontogenic lesions

Answer 12

-Exclude PA cyst/granuloma (should always be unilocular) and vitality testing
-OKC
-Ameloblastoma
-Other benign odontogenic tumor

Question 13

Central Giant Cell Granuloma

Answer 13

-Intrabony lesion of unknown cause
-Reactive? Some are small with no symptoms, slow growing (non-aggressive)
-Neoplastic? Others that are fast growing destructive with cortical perforation, root resorption or displacement, and can cause pain/paresthesia and extend into soft tissue (aggressive)
- 60% before 30yrs
-Usually affects the mandible, often in the anterior and can cross midline
-Most often it is a painless, expansile, unilocular/multilocular RL that can displace and/or resorb teeth

Question 14

Central Giant Cell Granuloma - Histology

Answer 14

-Multinucleated giant cells, fibroblasts, monocyte/mac type cells, RBCs, hemosiderin
-Tissue looks very dark brown

Question 15

Central Giant Cell Granuloma - dx, tx, recurrence

Answer 15

-Always rule out a brown tumor of hyperparathyroidism which tends to occur >60yrs where might see additional bone lesions
-Tx: if isolated, aggressive curettage
-Recurrence rate of 15-20% so follow-up

Question 16

Stafne Defect

Answer 16

-Also known as a Stafne bone cyst but NOT a cyst - a developmental depression in the bone due to normal salivary gland tissue (pseudocyst)
-Asymptomatic, well-circumscribed RL often with a sclerotic border of the posterior mandible below the inferior alveolar canal (submd gland) or occasionally anterior teeth
-Strong majority occur in men
-Although a developmental process, occurs in middle-aged to older adults
-CBCT helpful to confirm dx; no tx required

Question 17

Schwannoma/Neurofibroma in bone

Answer 17

-May be seen in the posterior mandible within the mandibular canal
-Well defined, uni-/multilocular radiolucency
-Pain and paresthesia may occur in bony lesions
-Tx: conservative excision, little tendency to recur

Question 18

Bony Vascular Malformations

Answer 18

-May be associated with other conditions/syndromes

Arteriovenous (AV) malformations- direct connection of arterial and venous channels
-If high pressure is maintained (high flow), biopsy or trauma can cause life-threatening hemorrhage)
-Ill-defined or cyst-like radiolucent defect, often multilocular
-May detect pulsation on palpation or bruit (abnormal sound) on ascultation
-Overlying skin is warm
-Yields bright red blood on aspirate
-Tx: embolization and/or excision

Question 19

Before opening into any radiolucent lesion always….

Answer 19

Aspirate!

Question 20

Focal Osteoporotic Marrow Defect

Answer 20

-Asymptomatic ill-defined radiolucency in body of mandible at old extraction site
-Middle-aged females
-May resemble metastatic disease; biopsy is sometimes necessary
-Fatty and hematopoietic marrow seen microscopically
-No tx necessary; not connected with a hematologic disorder

Question 21

RL malignancies involving bone - adults vs kids

Answer 21

-Look for pain (can mimic a toothache), tooth mobility, paresthesia (numb-chin sign), rapid growth/expansion, ill-defined borders
-In children: leukemia/lymphoma, rhabdomyosarcoma, Ewing Sarcoma
-In adults: metastatic carcinoma (most often mandible), lymphoma, multiple myeloma - multiple punched-out radiolucencies

Question 22

Non-Hodgkin Lymphoma

Answer 22

-Usually extranodal disease
-May be isolated or evidence of widespread disease
-In soft tissue:
1. non-tender, diffuse swelling
2. buccal vestibule, posterior hard palate or gingiva
3. Normal to red/purple, possibly ulcerated, often with a boggy consistency
-In the jaws:
1. vague pain (toothache-like), paresthesia, “numb chin” sign
2. Ill-defined/ragged radiolucency
3. With time, expansion and perforation into soft tissue

Question 23

Multiple Myeloma

Answer 23

-A common lymphoid malignancy
-Median age = 70yrs
-Primarily involves bone marrow with associated lytic lesions (often “punched-out” radiolucencies) throughout the skeleton (vertebral column, ribs, skull, etc)
-Most frequent M protein is IgG. If kappa or lambda light chains are produced their small size allows excretion in the urine (Bence-Jones proteins)

Question 24

Multiple Myeloma - Clinical

Answer 24

-Bone resorption causing chronic pain and pathologic fracture (class “punched out” radiolucencies)
-Hypercalcemia causes confusion, weakness, lethargy
-Recurrent bacterial infections
-Renal insufficiency
-Definitive diagnosis requires bone marrow exam

Question 25

Multiple Myeloma - Tx

Answer 25

-Chemotx (proteasome inhibitora)
-Bisphosphonates (drugs that inhibit bone resorption) reduce fracture and hypercalcemia
-W/o tx, death occurs within a year
-Some patients have “smoldering myeloma” that may be asymptomatic for many years
-Median survival: 4-7 yrs